PROTOBASIDIOMYCETES 



431 



produced in short chains and measure 24-28 x 18-21 fj, (Fig. 210, b). 

 The uredesori occur on the under surface of the leaf. They are 

 somewhat lighter colored than the casoma and are constantly 

 inclosed by paraphyses. Individual spores are about the same in 

 size and form, however, as the previous type (Fig. 210, c). In the 

 same sori with the latter may be produced also the teleutospores, 



Fig. 210. Phragmidium subcorticium 

 a and d, caeoma and teleuto stages on rose ; b : c, and e, spore forms 



usually in small black groups. A teleutospore is more or less 

 spindle-shaped, usually six to eight cells in extent (Fig. 210, e), and 

 each cell is provided with several germ pores. The outer wall of 

 the spore is generally uneven or warty toward the apex, and 

 there is a distinct terminal papilla. The teleutospores measure 

 65-100 x 30-45 \x without the pedicel. The pedicel is persistent, 

 swollen at the base, and about as long as the spore. The cells of 

 the teleutospore adhere closely, while in some other species they 

 separate readily on maturity. 



